The present technique relates generally to spray systems and, more particularly, to industrial spray coating systems. The present technique specifically provides a system and method for improving atomization in a spray coating device by internally mixing and breaking up the fluid prior to atomization at a spray formation section of the spray coating device.
Spray coating devices are used to apply a spray coating to a wide variety of produce types and materials, such as wood and metal. The spray coating fluids used for each different industrial application may have much different fluid characteristics and desired coating properties. For example, wood coating fluids/stains are generally viscous fluids, which may have significant particulate/ligaments throughout the fluid/stain. Existing spray coating devices, such as air atomizing spray guns, are often unable to breakup the foregoing particulate/ligaments. The resulting spray coating has an undesirably inconsistent appearance, which may be characterized by mottling and various other inconsistencies in textures, colors, and overall appearance. In air atomizing spray guns operating at relatively low air pressures, such as below 10 psi, the foregoing coating inconsistencies are particularly apparent.
Accordingly, a technique is needed for mixing and breaking up a desired coating fluid prior to atomization in a spray formation section of a spray coating device.
The present technique provides a system and method for improving atomization in a spray coating device by internally mixing and breaking up a desired coating fluid prior to atomization at a spray formation section of the spray coating device. An exemplary spray coating device of the present technique has a mixture-inducing valve disposed adjacent a flow barrier upstream of a spray formation exit. The mixture-inducing valve may have a variety of blunt/angled structures and internal passages to facilitate fluid mixing. The mixture-inducing valve also may interact with the flow barrier to enhance the fluid mixing and fluid breakup. One embodiment of the present spray coating device has an internal fluid breakup section, such as an impinging jet section, adjacent the mixture-inducing valve. The resulting spray coating has refined characteristics, such as reduced mottling.